Referring to FIGS. 1 and 1A, a prior art folding structure of a scooter is illustrated, the folding structure is disclosed by the Applicant of the present invention and is filed with a Taiwan Patent No. 89207153. In the prior art, one end of the linkage A is formed with a long hole and a round hole. A quick detaching means B passes through the long hole and one axial rod C passes through the round hole so that the linkage is pivotally connected to the folding means D. Thereby, the linkage A can be folded around the axial rod C by rotating within the folding means D. A stud is buckled into receiving grooves at top sides of a buckling block E extending upwards from the folding means. The quick detaching means B serves to engage the buckling block E with the linkage A. In this prior art, since the engagement of the quick detaching means B is not a preferred way and thus it will wear rapidly. Thereby, the linkage A and the folding means D can not be engaged with a preferred way. Moreover, if the user applies an improper force to the quick detaching means or makes a mistake as the user operates the quick detaching means, it will affect the safety of the driver. If it is desired to rotate the linkage A, a force must be applied to the stud of the quick detaching unit B so that the stud will release from the confinement of the buckling block E. Since the elastic force of the spring is very strong, the user must move the spring and then lifts the spring upwards. However, this operation is inconvenient.